JP4651860B2 - Fuel cell stack - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a fuel cell stack having an improved power take-out structure.
[0002]
[Prior art]
For example, a fuel cell stack in which a plurality of electrolyte / electrode structures sandwiching an electrolyte such as a solid polymer electrolyte membrane with a pair of electrodes are interposed via a separator, and terminal plates provided at both ends of the fuel cell stack, There are known fuel cell stacks having:
[0003]
In this type of fuel cell stack, a fuel gas, for example, hydrogen gas, supplied to the anode electrode is hydrogen ionized on the catalyst electrode and moves to the cathode electrode side through an appropriately humidified electrolyte. Electrons generated in the meantime are taken out to an external circuit through the terminal plate and used as direct current electric energy. Since the oxidant gas, for example, oxygen gas or air is supplied to the cathode electrode, the hydrogen ions, the electrons and the oxygen gas react with each other to generate water at the cathode electrode.
[0004]
An example of this will be described with reference to FIGS. 13 to 15. In the figure, reference numeral 1 denotes a fuel cell stack. The fuel cell stack 1 is formed by stacking a plurality of electrolyte / electrode structures each having a solid polymer electrolyte membrane sandwiched between a cathode electrode and an anode electrode via a separator. Reference numeral 2 denotes a terminal plate which is sandwiched between the fuel cell stack 1 by an end plate 3 disposed at the end of the fuel cell stack 1. A fuel cell stack is formed by inserting a stud bolt (not shown) into the fuel cell stack 1 with the terminal plate 2 interposed therebetween and tightening from both sides. A terminal connecting portion 4 is provided on the periphery of the terminal plate 2 in a direction along the surface of the terminal plate 2, and the terminal connecting portion 4 is connected to the tip of the power extraction cable 5 as shown in FIGS. 13 and 15. The portion 6 is fastened and fixed to the terminal connection portion 4 of the terminal plate 2 by bolts 7 and nuts 8.
[0005]
As shown in FIGS. 16 and 17, the terminal plate 2 superposed on the fuel cell stack 1 is formed with a protruding portion 9 perpendicular to the surface of the terminal plate 2, and the protruding portion 9 protrudes from the end plate 3. In some cases, the connecting portion 6 at the tip of the power take-out cable 5 is fixed to the stud bolt 10 attached to the tip of the protruding portion 9 with a nut 8 (see Japanese Patent Laid-Open No. 06-290803).
[0006]
[Problems to be solved by the invention]
However, in any fuel cell stack, the connecting portion 6 at the tip of the power take-out cable 5 is fastened with a bolt 7 or a nut 8. Therefore, for example, the fuel cell stack is used as in-vehicle use. When the vibration is applied to the bolt 7 and the nut 8, the bolt 7 and the nut 8 are easily loosened at the tightening portion. When the bolt 7 and the nut 8 are loosened in this way, a continuity failure occurs around the connecting portion 6 of the power take-out cable 5 and the contact resistance increases. As a result, there is a problem that electrical loss increases.
Accordingly, the present invention provides a fuel cell stack in which the connection portion between the terminal plate and the power take-off cable is not loosened even when vibrations are applied and no poor conduction occurs, and the connection state can be reliably maintained. .
[0007]
[Means for Solving the Problems]
In order to solve the above problems, the invention described in claim 1 is configured such that an electrolyte (for example, the solid polymer electrolyte membrane 12 in the embodiment) is formed by a pair of electrodes (for example, the anode electrode 13 and the cathode electrode 14 in the embodiment). A fuel cell stack (for example, in the embodiment) in which a plurality of sandwiched electrolyte / electrode structures (for example, the electrolyte / electrode structure 15 in the embodiment) are stacked via separators (for example, separators 16 and 17 in the embodiment) In a fuel cell stack (for example, the fuel cell stack 11 in the embodiment) having a fuel cell stack S) and terminal plates (for example, the terminal plate T in the embodiment) provided at both ends of the fuel cell stack, One terminal plate has a boss (for example, the boss 36 in the embodiment). A rod-shaped electrode member (for example, the pin 43 in the embodiment) connected to the power extraction member (for example, the power extraction cable 41 in the embodiment) can be inserted into the boss, and the boss and the electrode member can be inserted. An annular spring member (for example, the spring member 38 in the embodiment) that elastically contacts both is provided.
With this configuration, when connecting the power extraction member and the terminal plate, if a rod-shaped electrode member is inserted into the boss of the terminal plate, the spring member interposed between the electrode member and the boss is The conductive state of both can be secured by elastic contact with both.
[0008]
According to a second aspect of the present invention, there is provided a fuel cell stack in which a plurality of electrolyte / electrode structures having an electrolyte sandwiched between a pair of electrodes are stacked via a separator, and terminal plates provided at both ends of the fuel cell stack, The electrode member (for example, receiving member 54 in the embodiment) in which a pin (for example, the pin 53 in the embodiment) is provided on at least one of the terminal plates and the pin is connected to the power extraction member. An annular spring member (for example, a spring member 38 'in the embodiment) is provided between the pin and the insertion portion so as to be elastically contactable with the insertion portion (for example, the insertion portion 55 in the embodiment). It is characterized by that.
By configuring in this way, when connecting the power extraction member and the terminal plate, if the insertion portion of the electrode member on the power extraction member side is fitted to the pin of the terminal plate, the insertion portion of the electrode member and the pin Since the spring member interposed between the two is elastically contacted with each other, it is possible to ensure a conductive state between the two.
[0009]
The invention as set forth in claim 3, the outer end plate of the terminal plate in which the boss or the pin is provided (e.g., the end plate 24 in the embodiment) provided to said end plate, said electrode member is a boss Alternatively, a pressing member (for example, the pressing member 47 in the embodiment) that prevents the pin from moving in the pulling direction is fixed .
With this configuration, it is possible to prevent the electrode member from coming off from the boss or the pin .
[0010]
DETAILED DESCRIPTION OF THE INVENTION
Embodiments of the present invention will be described below with reference to the drawings.
1 and 2, reference numeral 11 denotes an in-vehicle fuel cell stack. The fuel cell stack 11 includes a fuel cell stack S and terminal plates T provided at both ends of the fuel cell stack S.
The fuel cell stack S includes a plurality of electrolyte / electrode structures 15 each having a solid polymer electrolyte membrane (electrolyte) 12 sandwiched between an anode electrode 13 and a cathode electrode 14 in the horizontal direction via separators 16 and 17. It is a laminated one.
[0011]
A hydrogen gas supply path 18 is formed between the anode electrode 13 and the adjacent separator 16, while an air supply path 19 is formed between the cathode electrode 14 and the adjacent separator 17. Further, a unit fuel cell in which a cooling medium such as pure water or ethylene glycol is supplied to the supply path 20 of the separator 16 positioned between the back surfaces of the separators 16 and 17 and the electrolyte / electrode structure 15 is sandwiched between the separators 16 and 17. The cell is cooled. For the sake of illustration, hatching indicating a cross section is omitted in FIG.
[0012]
In order to supply the hydrogen gas, air, and cooling medium to the supply paths 18, 19, and 20, the fuel cell stack S and each surface of the terminal plate T, the insulating plate 23, and the end plate 24 described later are provided. As shown in FIG. 2, communication holes 25, 26, and 27 are respectively formed so as to have an internal manifold structure.
[0013]
The terminal plate T is a conductive member formed of a metal material such as copper or stainless steel or a carbon material disposed at both ends of the fuel cell stack S. The terminal plate T is an insulating member made of resin or the like outside the terminal plate T. An end plate 24 is arranged via a plate 23 (shown in FIG. 3). A stud bolt 28 is inserted from the end plate 24 through the insulating plate 23 and the fuel cell stack S, and a nut 29 is fastened to the stud bolt 28 to constitute the fuel cell stack 11.
[0014]
As shown in FIGS. 1 to 4, the terminal plate T includes a conductive flat plate portion 35 surrounded by an insulating member 34, and a substantially vertical direction from the central portion of the flat plate portion 35, that is, the unit fuel cell. 15 and a cylindrical boss 36 that protrudes in the stacking direction and penetrates the receiving hole of the end plate 24. The boss 36 is fixed to the flat plate portion 35 by welding or screwing.
An annular groove 37 is formed on the inner peripheral surface of the boss 36, and a metal-made annular spring member 38 shown in FIGS. 6 and 7 is mounted in the annular groove 37. As shown in FIG. 6, the spring member 38 is formed in an arc shape on the inner peripheral side, and is formed to be easily bent by a slit portion 39 provided in the axial direction.
Here, as the spring member 38, a member provided with cutout portions 40 alternately from the upper and lower edges may be used instead of the slit portion 39 as shown in FIG. 8, and as shown in FIG. The spring member 38 may have a band shape. The outer peripheral portion of the boss 36 is covered with an insulating plate 23.
[0015]
On the other hand, in FIG. 4, reference numeral 41 denotes a power take-out cable (power take-out member), and a metal fitting 42 is attached to the end of the power take-out cable 41 by caulking, and a pin having a circular cross section (bar-shaped electrode member) is attached to the metal fitting 42. 43 is joined by brazing or resistance welding. The base of the metal fitting 42 and the pin 43 is covered with a rubber or resin grommet 45 attached to the end of the covering material 44 of the power take-out cable 41. A chamfered portion 46 is provided in the peripheral edge of the tip of the pin 43 to facilitate insertion into the boss 36, and is constant between the tip of the pin 43 and the surface of the fuel cell stack S when the pin 43 is inserted. Clearance is ensured.
The pin 43 connected to the power take-out cable 41 can be inserted into the boss 36. With the pin 43 inserted into the boss 36, the boss 36 is connected to the pin 43 as shown in FIG. A pressing member 47 having a semicircular shape in a top view for preventing movement in the pulling direction is attached to the end plate 24 by a bolt 48.
[0016]
Here, as shown in FIG. 3, a stepped portion 52 is formed in the outer peripheral edge of the receiving hole of the boss 36 of the terminal plate T formed in the end plate 24, and the stepped portion 52 is made of rubber and has a cap shape. A grommet 49 is attached. The grommet 49 closes most of the receiving holes of the terminal plate T, making it difficult for foreign matter to enter from here. A flange portion 50 is formed on the outer peripheral surface of the grommet 49, and the flange portion 50 is sandwiched and fixed between the pressing member 47 and the end plate 24.
[0017]
Here, as shown in FIG. 10, a ball 51 is interposed between the outer peripheral surface of the pin 43 and the inner peripheral surface of the boss 36, and the ball 51 is urged by a spring (not shown) so that the pin 43 and the boss It is also possible to engage 36 with a sense of moderation. Further, as shown in FIG. 11, an annular groove 37 may be formed on the outer peripheral surface side of the pin 43, and a spring member 38 may be provided here.
[0018]
In addition, the communication holes 25, 26, 27 shown in FIG. 2, specifically, the communication holes 25, 26, 27 of the end plate 24, are not shown in the drawings for supplying and discharging air, hydrogen gas, and cooling medium. Are connected to each other, and air, hydrogen gas, and a cooling medium flow in a U-turn through the fuel cell stack 11, and power is taken out from the two power take-out cables 41 to an external circuit.
[0019]
Next, the operation will be described.
In connecting the power take-out cable 41 to the terminal plate T, first, the bolts 48 in FIGS. 3 and 4 are removed, and the pressing member 47 and the grommet 49 are removed from the end plate 24. Next, when the pin 43 at the tip of the power extraction cable 41 is inserted into the boss 36 of the terminal plate T, the spring member 38 mounted in the annular groove 37 on the inner peripheral wall of the boss 36 is attached to both the boss 36 and the pin 43. Elastic contact. Therefore, the boss 36 and the pin 43, that is, the terminal plate T and the power extraction cable 41 are conducted.
Then, if the grommet 49 is attached to the stepped portion 52 of the receiving hole of the end plate 24 and then the pressing member 47 is fastened to the end plate 24 by the bolt 48, the pin 43 is prevented from coming off from the terminal plate T. Can be attached.
Therefore, for example, even when vibration is applied to the fuel cell stack 11 as in the case where the fuel cell stack 1 is used for in-vehicle use, the conductive state between the boss 36 and the pin 43 is ensured.
[0020]
According to the above embodiment, the terminal plate T and the power take-out cable 41 can be easily connected by simply inserting the pin 43 into the boss 36 as compared with the case where the bolt and nut are connected. While the fuel cell stack 11 is vibrated while the vehicle is running, the spring member 38 is elastically contacted with both the boss 36 and the pin 43 even when the vibration is applied, thereby ensuring a conductive state between the two. Therefore, the terminal plate T and the power take-out cable 41 can be reliably connected without poor conduction. Therefore, it is suitable as an on-vehicle fuel cell stack. Further, since the pin 43 having a circular cross section is used, pivoting of the shaft is allowed, and a biased force does not act on the power extraction cable 41.
As a result, the tightening portion is loosened due to vibration as in the prior art, and the contact resistance is increased and no electrical loss occurs, so that the reliability can be improved.
Further, by providing the pressing member 47 that prevents the pin 43 from moving in the pulling direction with respect to the boss 36 with the pin 43 inserted into the boss 36, the terminal plate T drops off the power extraction cable 41. Can be surely prevented.
[0021]
In this way, at the connection portion between the pin 43 and the boss 36, the spring member 38 is provided as a countermeasure against vibration, and the pressing member 47 is provided as a separate member as a countermeasure against slipping, so that the vibration by the spring member 38 acts. However, the conductivity is not impaired, and each function can be exhibited without adversely affecting each other.
[0022]
Next, a second embodiment of the present invention will be described with reference to FIG.
In this embodiment, the basic structure is the same as that of the first embodiment, but a concave receiving member (electrode member) 54 connected to the power take-out cable 41 is provided instead of the pin 43 in the first embodiment, Instead of the boss 36 of the first embodiment, the terminal plate T is provided with a pin 53 having a circular cross section. The pin 53 of the terminal plate T is configured to be insertable into the insertion portion 55 of the concave receiving member 54 connected to the power extraction cable 41. An annular groove 56 is formed on the inner peripheral wall of the receiving member 54, and an annular spring member 38 ′ that elastically contacts the pin 53 and the insertion portion 55 is attached to the annular groove 56. Since other configurations are the same as those in the first embodiment, the same reference numerals are given to the same portions, and descriptions thereof are omitted.
[0023]
Also in this embodiment, the terminal plate T and the power take-out cable 41 are simply connected by simply attaching the receiving member 54 to the pin 53 so that the pin 53 is inserted into the insertion portion 55 of the receiving member 54. Can do. While the fuel cell stack 11 is vibrated while the vehicle is running, the spring member 38 ′ is elastically contacted with both the receiving member 54 and the pin 53 even when the vibration is applied, thereby ensuring a conductive state between the two. Therefore, the terminal plate T and the power take-out cable 41 can be reliably connected without poor conduction. As a result, the tightening portion is loosened due to vibration as in the prior art, and the contact resistance is increased and no electrical loss occurs, so that the reliability can be improved.
[0024]
Moreover, since the receiving member 54 is prevented from coming off from the pin 53 by the pressing member 47 as in the above-described embodiment, the mounting reliability can be improved. In particular, in this embodiment, since the insertion portion 55 of the receiving member 54 attached to the power take-out cable 41 is inside the receiving member 54, it is not exposed to the outside like the pin 43 of the first embodiment. Only advantageous in that it is less susceptible to scratches and damage.
[0025]
The present invention is not limited to the above embodiment. For example, the boss 36 of the terminal plate is not limited to the through hole as long as the pin 43 can be inserted, and may be a recess. Moreover, although the case where the pins 43 and 53 were formed in the cross-sectional circle shape was demonstrated, various shapes, such as a triangle and a square, can be employ | adopted for cross-sectional shape.
[0026]
【The invention's effect】
As described above, according to the invention described in claim 1, when connecting the power extraction cable and the terminal plate, if a rod-shaped electrode member is inserted into the boss of the terminal plate, the electrode member and the boss Since the spring member interposed between them is elastically contacted with each other, the conductive state between the two can be ensured, so that there is an effect that the terminal plate and the power take-out cable can be connected without defective conduction even when vibrations are applied.
[0027]
According to the second aspect of the present invention, when the power take-out cable and the terminal plate are connected, if the electrode member insertion portion on the power take-out cable side is fitted to the pin of the terminal plate, the electrode member is inserted. The spring member interposed between the pin and the pin is elastically contacted with each other, so that the conductive state between the two can be ensured. Therefore, there is an effect that the terminal plate and the power take-out cable can be connected without poor continuity even when vibration is applied. .
[0028]
According to the invention described in claim 3, since it becomes possible to prevent the electrode member from coming off from the boss or the pin, it is possible to reliably prevent the power take-out cable from dropping off from the terminal plate. is there.
[Brief description of the drawings]
FIG. 1 is a cross-sectional view of a fuel cell stack according to a first embodiment of the present invention.
FIG. 2 is a cross-sectional view taken along the line AA in FIG.
3 is a cross-sectional view of a main part of FIG.
4 is an exploded view of FIG. 3. FIG.
FIG. 5 is a plan view showing the periphery of a pressing member.
6 is a cross-sectional view taken along the line BB in FIG.
FIG. 7 is a plan view of a spring member.
FIG. 8 is a cross-sectional view corresponding to FIG. 6 of another spring member.
FIG. 9 is a plan view of another spring member.
10 is an enlarged cross-sectional view of FIG. 3 with a retaining member attached.
11 is an enlarged cross-sectional view of FIG. 3 using another spring member.
FIG. 12 is a cross-sectional view corresponding to FIG. 3 of a second embodiment of the present invention.
FIG. 13 is a schematic front view of a conventional fuel cell stack.
FIG. 14 is a plan view of FIG. 13;
FIG. 15 is an enlarged view of a connection portion of the prior art.
FIG. 16 is a schematic front view of another prior art fuel cell stack.
17 is a plan sectional view of FIG. 16. FIG.
[Explanation of symbols]
11 Fuel Cell Stack 12 Solid Polymer Electrolyte Membrane (Electrolyte)
13 Anode electrode 14 Cathode electrode 15 Electrolyte / electrode structure 16, 17 Separator
24 End plate 36 Boss 38, 38 ' Spring member 41 Electric power extraction member (electric power extraction cable)
43 pins (electrode member)
47 Holding member 53 Pin 54 Receiving member (electrode member)
55 Insertion section S Fuel cell stack T Terminal plate

Claims (3)

  In a fuel cell stack having a fuel cell stack in which a plurality of electrolyte / electrode structures sandwiching an electrolyte between a pair of electrodes are interposed via a separator, and terminal plates provided at both ends of the fuel cell stack, at least A boss is provided on one of the terminal plates, and a rod-shaped electrode member connected to the power extraction member is inserted into the boss, and an annular spring member that elastically contacts between the boss and the electrode member is provided. A fuel cell stack characterized by being provided.   In a fuel cell stack having a fuel cell stack in which a plurality of electrolyte / electrode structures sandwiching an electrolyte between a pair of electrodes are interposed via a separator, and terminal plates provided at both ends of the fuel cell stack, at least A pin is provided on one of the terminal plates, the pin is configured to be insertable into an insertion portion of an electrode member connected to a power extraction member, and an annular spring member elastically contacting both between the pin and the insertion portion. A fuel cell stack characterized by being provided. An end plate is provided outside the terminal plate on which the boss or the pin is provided , and a pressing member for preventing the electrode member from moving in the pulling direction with respect to the boss or the pin is fixed to the end plate. the fuel cell stack according to claim 1 or claim 2, characterized in that the.

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